Abstract Detail

Speciation Mechanisms in Plants

Coughlan, Jenn [1].

The evolution of hybrid seed inviability in a group of cryptic perennial Mimulus.

Genomic conflicts may play a central role in the evolution of reproductive barriers. A common barrier in plants is Hybrid Seed Inviability (HSI), which may evolve via conflict between maternal and paternal interests in resource allocation to offspring (i.e. parental conflict). Under parental conflict, inviable hybrids are the manifestation of mismatched maternal and paternal alleles which results in inappropriate hybrid growth, and eventually death. Here I test the role of parental conflict in HSI using members of the evolutionary and ecological model system; the Mimulus guttatus species complex. Using a combination of population genomics and crossing surveys, I uncovered a cryptic species complex- M. decorus- within the M. guttatus species complex that are largely reproductively isolated by HSI. Patterns of HSI conform to the predictions of parental conflict: (1) reciprocal F1s differ in seed size and endosperm development, (2) the extent of differences between reciprocal F1s is correlated with the severity of HSI, and (3) differences among species in their inferred history of conflict is predictive of the extent of reproductive isolation. Moreover, HSI is rapidly evolving, as the two species with the most extreme histories of conflict and the strongest reproductive isolation are each other’s closest relative. Lastly, using a series of natural surveys and mixed pollination crosses, I find that species with different histories of parental conflict frequently co-occur and hybridize, and hybridization between species with differing histories of conflict can contribute to indirect growth effects of conspecific seeds when these seeds develop alongside hybrid siblings. Overall, I find a substantial amount of cryptic diversity within a model system for ecology, evolution, and genetics, provide an example of rapidly evolving reproductive isolation driven by conflict, and highlight a dual role of parental conflict in the speciation process.

1 - University Of North Carolina, Chapel Hill, 250 Bell Tower, Suite 3161, Coker Hall, CB #3280, Durham, NC, 27705, United States

Reproductive Isolation

Presentation Type: Colloquium Presentations
Number: 0010
Abstract ID:94
Candidate for Awards:Margaret Menzel Award

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